Pneumatic draft regulator



July 15, 1930. w. J. cooK PNEUMATIC} DRAFT REGULATOR Filed July 2, 19282 Sheets-Sheet l w Qi/A ENTUR v W ATTDAIYE'VE' July 15, 1930. w. J. cooK1,770,588

PNEUMATI 0 DRAFT REGULATOR Filed July 2, 1928 I 2 Sheets-Sheet 2 W/TNEss g i A7701? EYS Wwez 1576 Patented July 15, 1930 UNITED STATESWALTER J. COOK, OF GENEVA, NEW YORK Pia-numer c naar'r REGULATORApplication filed July 2,

This invention relates to a new and improved pneumatic draft regulatorfor use with forced draft systems for boilers and furnaces. p

In order that low grade or finely divided fuel may be used in heatingboilers and furnaces it is necessary that some means be provided wherebyair ma be fed to the bed of fuel with greater rapi ity and in greatervol ume than would be given by a natural draft.

This result is usually accomplished by providing an electric motor'fromwhich is operated a fan or blower which sends air into the ash pit ofthe boiler or furnace underneath the bed of fuel. L Such electric motormay be started and stopped manually, if desired, but is usuallycontrolled by thermostatic means. When air under pressure is being sentinto the ash pit of a boiler or furnace no opening other than theopening through which the 1 air enters-can be present in the ash pit because if it were the air under pressure would expel ashes and embersfrom the ash pit into the furnace room. This being the case in all ofthe forced draft systems known to the art it has been customary uponinstallation to hermetically seal the clean out door and draft doorwhich is usually present in the ash pit of the boiler or furnace. Whenthis is done'the only draft which can ever be furnished for the firemust come from the blower. Under these conditions there can be no draftfor the fuel when the blower is not operating. Such an arrangement isuneconomical because of the fact that it does not take advantage of thenatural draft when the blower is not operating. In other words, the

bed of fuel is either subjected to a draft under pressure; or it isdeprived of any draft at all.

Furthermore in installations of this character there is a strongpossibility that unburned gases will accumulate on the surface of thefuel, whichv gases frequently are ignited when the blower is started andthe bed of fuel again placed under forced draft; Such ignition ofaccumulated gases "will 0 cause an explosion which'may and sometimesdoes cause considerable damage.

1928. Serial No. 290,013.

The main object of my invention is to con struct a means which may beused in con junction with a forced draft system and be operated thereby,which means will insure that the ash pit will be closed while the bloweris in operation but which will. cause the'opening of a door into the ashpit when the blower ceases operation so that the bed of fuel may thenreceive the natural draft which the boiler or furnace itself provides.

Another object is to provide a means whereby the evacuation of unburnedgases from the fire pot of the boiler or furnace will be accelerated. 7

Another object is to provide a means for utilizing a portion of the airfrom the blower to assist in the combustion of the fuel.

Other objects and advantages relate to the size, shape and arrangementof parts all-as will more fully appear from the following descriptiontaken in conjunction with the accompanying drawings in which Figure l isan elevation, partially broken away, of a boiler and blower with myapparatus .installed. Figure 2 is a section on line 22 of Figure 1. Y

Figure 3 is a longitudinal vertical section through my device.

Figure 4 is an elevation, partially broken so away, and partially insection 0 my device.

Figure 5 is a section on line 55 of Figure 3. v

Figure 6 is a vertical view, partially in section, of my air jet. Mdevice may be used in conjunction with any iler or furnace with whichthe forced draft system is'used but for the purpose of explaining thefunctioning of my device I have here shown a boiler 1 of the typeusually called a round boiler having the usual ash pit 2, fire pot 3 andheader 4 It is also provided with the usual g clean-out door .-5, draftdoor 6-, clinker door .7 and fuel door -8 I 5 A blower 9 operated fromany convenient source of power, none being here. shown, is located,adjacent the ash pit 2- p with a discharge opening 10 in communicationwith the ash pit The grates, v 3

not shown, on which the fuel -11' is supported are positioned on the topof the ash pit so that the air from the blower 9 will strike the bottomof the bed of fuel 11. The products of combustion are removed from theboiler through the ordinary smoke stack 12-.

A regulator bar --13 is pivotally mounted above the boiler and hasdepending from one end a chain -11 connected to the draft door 6-so'that the pivoting of the regulator bar 13 about its pivot will openor close the draft door -6. On the opposite end of regulator bar 13- isprovided a weight -l5normally holding that end of regulator bar beneaththe pivot which will cause the chain 14- to be moved upwardly to holdthe draft door 6 in the open position; I also provide a diaphragm 16 inoperative contact with the end of the regulator bar 13 from which chain-14 depends. Diaphragm -l6- is connected to the steam chamber, notshown, in header 4 so that when a certain amount of steam is present thediaphragm 16 will be forced downwardly to overcome the action of weight15 with the result that chain 14 will be lowered and draft door 6closed.

My draft regulator -17 is positioned between ash pit -2 and blower 9' anconsists of an inlet head 18- to which is connected the dischargeopening --10 of the blower -9. Inlet head '18- is preferably made ofcast iron and carries at its forward'end a gate -19 hook shaped in crosssection and being pivotally mounted in the top edge of inlet head 18.Inlet head 18 is provided on its inner end with opposed flanges -20-,one only being shown,

of a size and shape conforming with the size and shape of gate 19 sothat when gate 19 is in the down position its edges will contact withflanges -20 to close the opening through inlet head 18-. Gate 19 carriesa shaft -21- which is journaled in inlet head 718- and extends outwardlytherefrom, shaft 21 being the pivot from which gate 19 is suspended. Ialso provide on the bottom of inlet head -18 a baflle 22 extendingoutwardly and upwardly and so ositioned that gate 19 when pivoted wi bemoved along the upper A discharge head -23 preferably made On the top ofinlet head \,-18 is provided an upwardly extending air tube --26+-carrying a-regulating damper -27-. Air tube -26 has an opening in itsbottom end angularly disposed with relation to discharge opening 10 ofblower 9 so that when air is being discharged through discharge opening10 a portion of such air will enter air tube 2( and proceed upwardlytherethrough.

In the upper surface of discharge head -'-23 is a second air tube 28which extends upwardly therefrom and which is provided with a damper-29-. Air tube 28- has a spoon shaped lower end which extends downwardlyinto the path of the air passing through discharge head 23 so that aportion of such air will enter air tube 28- and proceed upwardlytherethrough.

The upper end of air tube 28 is connected to an air jet -30 which ispositioned on the inside of smoke stack -12 with its discharge openingpointing upwardly;

Air tube 26 extends laterally into fire pot 3 and carries on its end adischarge nozzle 31 which is positioned above the fuel 11-. Dischargenozzle -31-, as perhaps may best be seen from Figure 2, is preferablyformed with a curved forward end 32 in which are provided a plurality,in this case shown as seven, of apertures 33- in spaced relation so thatthe air passing through air tube -26 into discharge nozzle 31 will bedistributed through apertures -33- to different parts of fire pot 3-.

d Air tube 26 is held in position in fire pot -3- by means of lock nuts34-- and 35, air tube 26 being threaded for such purpose.

As perhaps may best be seen from Figures 4 and 5, shaft 21 carrying gate19 carries a crank 36- Crank 36-, as perhaps may best be seen fromFigure 1, is connected by means of a chain '37 passing through a pulley-38 to the end of regulator bar 13- on which weight 15 is positioned sothat the downward movement of crank 36 caused by the rotation of shaft21- will cause the end of regulator bar 13 to which it is attached to bemoved upwardly thereby causing chain -14 to move downwardly and permitdraft door -6 to close. Crank -36, as perhaps may best be seen fromFigure 4, is so disposed with relation to gate -19 that the upwardmovement of gate 19 will cause the downward movement of crank 36 due tothe rotation of shaft -21- and conversely the downward movement of gate19 will cause the upward movement of crank 36. In F igure 4 I show inheavy lines gate --19 closed with crank -36 in the up position and Ishow in dotted lines gate 19 in the raised position and crank -36 in thelowered position.

When the blower 9 is not operated the relation of parts is as shown inFigure 1 with draft door 6 open and with crank 36 in the raisedposition. When blower 9 is started in operation the air passing throughdischarge opening and inlet head -18 will strike gate 19- and force itupwardly and the continuing current of air will hold gate -19 in thisraised position. The operation of raising gate 19' is facilitated due tothe spoon shape of gate -19- and also due to the fact that the baflle 22is so disposed as to direct the air current against the face of gate-19. When gate 19 has thus been raised crank -36- will have been moveddownwardly which will cause regulator bar 13 to be pivoted and draftdoor 6 closed. 7

When blower 9 is stopped and no air,

is moving through discharge opening 10- and inlet head 18 gate -19 willdro to the closed position which will cause crank -36 to be raised, thisin turn will loosen chain -37 and permit weight 15 to 'move downwardlypivoting regulator bar --13 and raising chain -14 which will result inthe opening of draft door --6 to permit the fuel -11 to receive thenatural draft provided by the boiler 1.

When blower 9 is operating a supply;

of air will be forced through air tube 28 and out through air jet 3()into smoke stack .12. s discharge of air upwardly in smoke stack 12willfinaterially in-.

crease the suction in smoke stack 12-- and will accelerate the removalof the products of combustion from the fire pot 3 therebypreventing anyaccumulation of unburned gases in smoke stack 12.

The amount of air which it is desired to send through air tubes 26 and28 can be regulated as desired by means of dampers --27- and 29,respectively.

' It will be understood that the size of the different parts of myapparatus may be varied as desired depending upon the type of boiler orfurnace with which my device is to be used.

It will also be understood that the opening and closing of draft door--6.- may be accomplished irrespective of any steam regulation by meansof a diaphragm --16 as above described, the onlyrequirement being aregulator bar such as 13, a wei ht --15 and chains 14 and 37, for athough I have shown and described a specific structure and form of partas an exemplification of an embodiment of my invention I do not'desire'to lation of parts as various changes maybe restrict myself tothe exact shape, size or remade the scope of the appended claims.

' I claim:

1. In a fuel burning apparatus, an ash into the ash pit, means foropening such door,- an exhaust flue leading from the fire pot, a'source. of air under pressure, means for introducing such air into theash pit, means actuated by the air under pressure for closing the draftdoor, and means for introducing. air under pressure into the fire pot.

2. In a fuel burning apparatus, an ash pit, a bed of fuel above the ashpit, a fire pot above the bed of fuel, a draft door opening into the ashpit, means for opening such door, an exhaust flue leading from the firepot, a source of air under pressure, means for introducing such air intothe ash pit, means actuated by the air under pressure for closing thedraft door, means for introducing air under pressure into the fire pot,and additional means for introducing air under pressure into the exhaustflue. v

3. In a fuel burning apparatus having a draft door, means for openingsuch draft door, a source of air under pressure, means for introducingair under pressure into the fuel burning apparatus, means actuated bythe air under pressure for closing the draft door, such means includinga, gate pivotally -pit,'a bed of fuel above the ash pit, a fire potabove the bed of fuel, a draft door opening mounted in the path of theair under pressure.

4. In a 'fuel burning apparatus having a draft door, means for-openingsuch draft a door, a source of air under pressure, means for introduc ngair under pressure into the fuel burningapparatus, means actuated by the,air under pressure for closing the draft door,

such means including a gate pivotally mounted in the path of the airunder pressure, and a bafile for directing the air under pressureagainst the gate.

' 5; Ina fuelburning apparatus, an ash pit,

a bed of fuel above the ash pit, a fire pot above thebed of fuel, adraft door opening into the. ash pit, means for opening such door, anexhaust flue leading from the fire pot, a source of air under pressure,means for introducing such air into the ash pit, means actuated by theair under-pressure for closing the draft door, and means for introducingair under pressure into'the fire pot, such last named means including apipe having a portion 7 thereof in the path of the air under pressure.

no l

6. In a fuel burning apparatus, an ash pit,

a bed of fuel above the ash pit, a fire pot above the bed of. fuel, adraft door opening into the ash pit, means for opening such door, anexhaust'flue leading from the fire pot, a. source of air under pressure,means for introducing such air into the ash pit, means actuated bytheair under pressure for closingthe draft door, means for introducing airunder pressure into the fire pot, and additional means for introducingair under pressue into the exhaust flue, such last named means ineluding a'pipe having a portion thereof disposed in the path of the airunder pressure.

In witness whereof I have hereunto set my hand this 25th day of June,1928.

WALTER J. COOK.

